WO2006/059053, the contents of which are incorporated herein by reference, describes a method for fingerprinting video that involves identifying motion within the video and using a measure of the identified motion as a fingerprint for later identification of the video or a copy of that video.
By comparing each frame of a video against the previous frame, motion fingerprints can be created. Differences between the two frames are flagged as motion. A measure of the motion of each frame relative to the preceding frame is calculated by summing the differences in colour between the frames to give a single motion figure that is indicative of the relative motion between them. After the entire video has been processed a mean value is calculated. To save space and speed up matching, motion measurements below the mean are removed, so that only peaks above the mean are extracted. Then, the remaining information is used as the video motion fingerprint.
In practice, a plurality of video fingerprints is stored in a suitable database for use if and when video content is detected. In the event that such content is detected, it is captured and a motion fingerprint automatically created. This is then compared with the fingerprints in the database to identify whether there is a match between the fingerprint of the captured video and any of the stored fingerprints. In the event that there is a match, this is indicative that the intercepted video is a copy of the original and may be a copyright infringement. If this is the case, remedial action can be taken against both the source and the intended recipient of the infringing copy.
The present invention relates to an improved technique for fingerprinting video and identifying unknown video using stored fingerprints.